The invention relates to a Faraday cage, particularly for Nuclear Magnetic Resonance applications, having walls which delimit a room, said walls being at least partially made of an electrically conductive material and connected to the ground or to a predetermined potential.
Although various solutions have been proposed for suppressing electromagnetic noise, such as grounding the patient body and/or the medical staff by appropriate arrangements, or using self-shielding equipment, the best solution always consists in a Faraday cage electromagnetic shield enclosing the equipment, the patient and the medical staff, when needed. Faraday cages are known in many different construction forms. Nevertheless, prior art cages do not solve, but increase in a sense, the problem of the static load of the Nuclear Magnetic Resonance imaging machine lying on the floor of the installation room. In fact, the machine load is added to the cage load.
Nuclear Magnetic Resonance imaging machines are very heavy and their huge weight is concentrated on a comparatively limited bearing surface.
This reduces considerably machine installation possibilities and, when installation rooms with suitable floors are not available, the installation of the machine requires costly building works for strengthening the floors in order that they can bear the load.
The invention has the object to provide, by simple and relatively inexpensive arrangements, a Faraday cage which allows to obviate the above problem thanks to a more flexible machine installation, especially for machines of the dedicated type, which are designed to ensure the maximum handiness and ease of use.
The invention also has the object to improve a Faraday cage such as the one described hereinbefore so as to make it more economical, safe and attractive for customers.
The invention achieves the above purposes by providing a Faraday cage as described hereinbefore, having a floor which rests at least partly on the ground of the installation room and having such a construction that the weight is spread all over its surface.
In order to provide such a floor, any currently known building techniques and materials, particularly in the field of metal building may be used.
Advantageously, the floor of the Faraday has a bearing structure.
According to a preferred characteristic, the bearing structure preferably has a plurality of beams which are only parallel, or inserted in a peripheral framework or connected to each other at the ends of the peripheral walls of the cage or alternatively crossed, and a plurality of panels, also load-bearing, therebetween, whose size corresponds to the free space between the beams.
The panels may be fastened to the beams in such a manner as to be integral therewith and to form a whole bearing structure.
Alternatively, the panels only rest on the beams.
The panels may be shaped in such a manner as to lay on the ground or be lifted therefrom in the area between the load bearing beams.
The panels may be of any type and material.
They can be made of an electrically conductive material and connected electrically and mechanically to the beams or have a composite structure with at least a layer made of a conductive material which is electrically connected to the beams.
The panels may be made of various materials, such as metal, wool, plastic, and the like or combinations of said materials.
Composite panels may be used, having at least one inner honeycomb or grated core which is externally covered at least on one side with a flat plate.
Preferably, both outer sides are covered with a flat plate, which can be identical on both sides.
Particularly, advantages resulted from using a panel having a honeycomb aluminum core, covered on both faces with an aluminum plate.
One of the plates, e.g. the one designed to form the walking surface may be covered with a plastic plate or the like directly on the core or applied on the covering aluminum plate.
Wooden or plastic panels may be also used, by providing, for example, on the contact face between the latter and the beams a metal network or simple load bearing grates.
The cage itself may have any construction, preferably modular and prefabricated as well as enabling installation without requiring building works.
It has to be observed that the floor may also not be bound to the cage construction and installed later.
When the cage is modular and especially when the floor is in the form of prefabricated parts, they can be composed of a limited number of different types of substantially identical construction parts within the same type range. For instance, the walls may all be made by assembling elements of the same type, and the same may be provided, for instance, for opening/closing means.
Thanks to the above arrangements, a Faraday cage may be provided, particularly for MRI applications which, besides providing an effective electromagnetic shield, also allows to spread the weight of the machine over a large surface of the floor of the installation room, thereby limiting any requirement for strengthening or consolidation works on the floors.
Further characteristics and possible improvements of the invention will form the subject of the dependent claims.
The characteristics of the invention and the advantages derived therefrom will appear more clearly from the following description of a preferred embodiment;